ABSTRACT: ORBITEC proposes to develop the Cooling Channel Diagnostic System (CCDS), a diagnostic tool for assessing the condition of rocket engine cooling channels. This system will be used to detect and locate any deposits which inhibit heat transfer between cooling channels and the hot-gas wall of the combustion chamber. The CCDS will detect and characterize any barriers to heat transfer which would degrade the performance of the cooling channels during engine operation, including coke buildup from hydrocarbon coolants, heavy layers of copper sulfide, channel-clogging debris, or other potential problems. Regions with coke buildup or other problems will be immediately detected by this diagnostic tool. In addition to identifying any such problems and pinpointing their location, the CCDS will also be able to characterize their severity. The CCDS will be a valuable tool for precisely mapping and characterizing any impediments to proper cooling. In Phase I, we will design, analyze, build, and test a subscale test article to demonstrate the operation and effectiveness of the CCDS. BENEFIT: The U.S. Air Force is the obvious first customer for CCDS systems once they have been successfully demonstrated and developed. The CCDS will also be an attractive diagnostic system for any other liquid rocket engines (reusable or single-use, hydrocarbon or hydrogen fuel) which utilize cooled chamber walls. Given the highly specific nature of the CCDS mission, we understand that the market for the technology will necessarily be limited, but nonetheless we feel that the CCDS will become an important tool for pre-flight test operations. During the Phase I and Phase II work, we will continually assess the market and work to build the relationships necessary for transitioning of this technology.